As a prior art printer of this type, a page printer represented by a laser printer is used widely.
Such a page printer, as shown in FIG. 8, is configured so that a hopping roller 3 feeds a sheet of paper of B5, A4 or other standard size one after another from a paper supply cassette 1, and as the paper moves along a paper transporting path 4, a mechanism including a sensitive drum 5 and others transfers letters or the like corresponding to printing patterns on the paper. More specifically, the sensitive drum 5 having an axial length larger than the maximum width of the paper 2 is rotated in arrow A direction in FIG. 8, and an electrifier 6 located around the sensitive drum 5 electrifies the sensitive drum 5 uniformly. Subsequently, a photographic writing unit 7 writes an electrostatic latent image corresponding to a printing pattern on the sensitive drum 5, and a developing unit 8 selectively attaches toner to the electrostatic latent image on the sensitive drum 5 to form a toner image. When the toner image reaches a transfer unit 9 during rotation of the sensitive drum 5, it is transferred from the sensitive drum 5 to the paper 2 by an electrostatic attractive force of the transfer unit 9. After this, the paper 2 is detached from the sensitive drum 5 and transported to a fixing unit 10 to thermally or pressingly fix the toner image on the paper 2 therein, and the paper 2 is discharged on a paper discharge tray 11. On the other hand, the sensitive drumb 5 passing through the transfer unit 9 loses the residual electric charge thereon due to operation of a deelectrifier 12, and the remainder of the toner on the sensitive drum 5 is subsequently removed by a cleaner 13.
In the prior art page printer, however, since the sensitive drum 5 has an axial length larger than the width of the paper, the substantially same axial lengths are required for the electrifier 6, photographic writing unit 7, developing unit 8, transfer unit 9, deelectrifier 12, cleaner 13 and others which are located around the sensitive drum 5. This necessarily increases the entire dimension of the page printer, and causes an increase in the manufacturing cost.
In order to overcome the problem, the Assignee of the present application already proposed a small-scaled, inexpensive printer capable of effecting a high-quality printing, using a laten image carrier in the form of an endless belt travelling in the width direction of the paper 2 in lieu of the photosensitive belt 5 having an axial length longer than the width of the paper 2.
The present invenion is proposed in view of these circumstances.